The Carbon Mitigation Initiative (CMI) at Princeton University is the longest running partnership with industry in the university’s history. Sponsored by bp and independently operated and administered by the High Meadows Environmental Institute (HMEI), CMI funds 15 principal investigators (PIs) and over 50 researchers who are tasked with finding compelling and sustainable solutions to the carbon and climate problems.

For 22 years, CMI has been leading the way in developing cutting-edge research in engineering, ecology, earth sciences, and environmental policy. This research has led to new insights into the impacts of climate change, developments in environmental engineering principles, and to salient policy recommendations and analyses that continue to impact the scientific and policy-making spheres, both domestically and internationally.

In this report, readers can find the latest information about CMI’s key activities and research initiatives. Each of the fourteen highlights, written by CMI PIs and their teams, features a summary of the latest, on-going research conducted by their groups. The Highlights section is followed by a complete list of this year’s CMI publications.


Ongoing Initiatives

Despite the COVID pandemic of the last two years, CMI researchers have maintained unabated research progress. One research initiative, which continues to gain traction globally and from which new projects were borne, The Net-Zero America project, has had outsized impact on policymakers and scientists in the US and abroad. Evolving from Net-Zero America, the REPEAT project allows policymakers and the public to view the impacts of proposed climate and energy policies before they are voted into law.

Another focus of CMI research in 2021 was carbon capture and storage (CCS), an important component in the transition to net-zero. Indeed, most models that show the economy achieving net-zero by 2050 rely heavily on this technology. CCS can be deployed by using hubs that carry CO2 from various capture sites via pipeline networks to a centralized injection site. One 2021 CMI highlight posits that CCS will be limited by large-scale geologic limitations on the rate at which CO2 can be injected. Another group of CMI researchers built a computer simulation tool to predict how geologic conditions can impact larger-scale geological carbon storage. Addressing the disconnect between CCS ambitions and constraints is crucial to successful CCS investment and policy decisions.

Other initiatives in the CMI research realm described in more detail in the following section include:

  • Determining the impact of aerosol particles on global radiative forcing
  • Consequences of hydrogen leakage on atmospheric methane
  • Impacts of wetlands on methane emissions
  • Predicting biodiversity responses to climate change
  • Carbon capture through mineral-carbon interactions in water
  • Using mathematical models to predict future climate
  • Impacts of climate and fire on the fate of Amazonian forests
  • Predicting reduced oxygen levels in the world’s oceans
  • Understanding the frequency of tropical cyclones
  • Using calcium compounds for carbon capture


Annual Meeting

For the second consecutive year, the CMI Annual Meeting was held virtually in April 2021. Despite the lack of in-person interaction, the meeting allowed over 100 participants to come together from across the globe. The virtual program included several deep dives that explored a variety of energy and land-based climate solutions.

Speaking to over 100 attendees, Stephen Pacala, the Frederick D. Petrie Professor in Ecology and Evolutionary Biology and the Director of CMI opened the meeting stating, “There seems to be a recognition happening all at once in different parts of the world, in companies, board rooms, halls of government and the academy, that the transformation of our energy system to net-zero emissions of all greenhouse gases is feasible, economic and necessary.”


Stephen Pacala (left), the Director of the Carbon Mitigation Initiative (CMI), and Kelly Goddard (right), former Vice President for Carbon Ambition at bp and the bp executive sponsor of CMI, opened the 2021 CMI Annual Meeting held virtually on April 20-21.


During her welcoming remarks, Kelly Goddard, then Vice President for Carbon Ambition at bp and CMI’s bp executive sponsor remarked, “In early 2020, bp announced its ambition to become a net-zero company by 2050 or sooner, and to help the world get to net-zero. bp is now over one year on from announcing this ambition and we’re pleased that we have made progress against what we have planned. Societal expectations and calls for action continue to increase, reinforcing what we have set out and the need for collaboration to support action.”

“We continue to see our long-term collaboration with Princeton’s CMI as an important science and technology partnership and we value the research being done by CMI to help the understanding of challenges and opportunities in the energy transition. Over the next two days, we will hear about the relevance of this research to bp and to broader stakeholders including policymakers,” said Goddard.

The meeting’s first deep dive included speakers from the Biden Administration, non-governmental organizations, and bp who discussed the role of carbon capture utilization and sequestration (CCUS) in net-zero energy systems in the U.S., Australia, China, and Europe.

In another deep dive, CMI leadership team members and principal investigators, Jonathan Levine and Amilcare Porporato, described a newly launched CMI initiative aimed at determining how land-based climate solutions can be deployed globally to maximize carbon storage on land, while at the same time maintaining global biodiversity and food security

“If we are going to actually achieve net-zero at a global level, country level or even a company level, land-based climate solutions must be deployed at massive spatial scales to have impact,” said Levine.

In addition, Pacala announced the following recipients of two awards named in honor of Robert H. Socolow, Emeritus Professor of Mechanical and Aeronautical Engineering at Princeton and CMI Co-director from 2000 to 2019.


Best Paper Awards 2020

Since 2010, the CMI Best Paper Award for Postdoctoral Fellows has been presented annually to one or two CMI-affiliated postdoctoral research associate(s) or research scholar(s) selected for their contribution to an important CMI paper. In late 2019, CMI created a similar award honoring a CMI-affiliated doctoral student for their contributions to an important CMI paper.

Former Postdoctoral Researcher Erin Mayfield, now an assistant professor at Dartmouth College, received the Robert H. Socolow Best Paper Award for Postdoctoral Fellows for her work on the Net-Zero America report. The second Robert H. Socolow Best Paper Award for Doctoral Students was given to Ching Ho Justin Ng, who received his Ph.D. in Atmospheric and Oceanic Sciences from Princeton in 2019, for his paper “Large-scale environmental controls on the seasonal statistics of rapidly intensifying North Atlantic tropical cyclones,” published in Climate Dynamics.

Erin Mayfield (left), a postdoctoral research associate in the High Meadows Environmental Institute received the Robert H. Socolow Best Paper award for the Postdoctoral Fellows. Justin Ng, who received his Ph.D. in Atmospheric and Oceanic Sciences from Princeton in 2019, was awarded the Robert H. Socolow Best Paper Award for Doctoral Students.


In addition to the external collaborations undertaken through the Princeton-led Net-Zero America project and the National Academies of Sciences, Engineering and Medicine Committee on Accelerating Decarbonization of the U.S. Energy System, CMI continued its engagement with three excellent research programs bp has long supported: the Center for the Environment at Harvard University; the Center for International Environment and Resource Policy at Tufts University; and the Thermal Engineering Department and the Tsinghua-bp Clean Energy Research and Educational Center at Tsinghua University.


New Collaborative Initiative

In 2021, CMI established a new initiative, Land-Based Climate Solutions: Variable Responses to Economic Incentives, in collaboration with University of California Santa Barbara and the Environmental Defense Fund. The project seeks to understand how economic, institutional, political, and cultural differences between countries are likely to affect the outcome of policy incentives encouraging private landowners to internalize climate impacts in their land-use decision making. The econometric analysis is expected to be completed in 2024.


Honors and Appointments

In 2021, CMI scholars were awarded with honors and appointments. Steve Pacala was appointed member of the President’s Council of Advisors on Science and Technology (PCAST); Gabriel Vecchi was appointed Director of the High Meadows Environmental Institute; Laure Resplandy received an National Science Foundation Career Award to study the formation and future of Pacific and Indian Ocean dead zones; and Jesse Jenkins was awarded the Undergraduate and Graduate Engineering Council Award for Excellence in Teaching.